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  <title>Document</title>
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  <script>
    // 转数字
    // 用+号
    let a = "123";
    console.log(+a);

    // 转字符串
    let b = 123;
    console.log(123 + "");

    // 转布尔值
    let c = "false";
    console.log(!!c);
    
    
  </script>
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